Study Of Sudden Cardiac Death Exposes Limits Of Genetic Testing

From NPR:

The findings, published online Wednesday in the New England Journal of Medicine, have implications far beyond this particular inherited disease, called hypertrophic cardiomyopathy, or HCM. Researchers say the results also sound a cautionary note for many other illnesses that have been identified through genetic markers.

HCM gained attention in the 1980s after several seemingly healthy athletes, including the rising basketball talent, Hank Gathers, suddenly died from it. Scientists had figured out that the propensity for developing HCM is passed along as a genetic trait; the condition affects about one in 500 Americans.

Tarika Mingo, a psychiatric social worker in New York City, first realized something was wrong with her own heart several years ago, when she became so short of breath during gentle activity that she nearly passed out. In 2014 her doctors accurately diagnosed her with HCM. They performed open-heart surgery and reduced her risk of sudden death. She still feels the effect of the disease, however.

“I have to see the cardiologist every three to six months,” she tells Shots. “I have to take my medicine every day. The heat is not my best friend, so it limits my social activities. We just had a heat wave and I was stuck in the house.”

The diagnosis also sent reverberations through her family. That’s because the likelihood of developing HCM follows a simple, inherited pattern: If your parent has the disease, your likelihood of developing it is 50:50. So she urged her entire family to get checked out. Mingo’s 16-year-old son shows no signs of having inherited the condition, but her 29-year-old sister has some ominous symptoms.

As part of the diagnosis, doctors turn to genetic testing. But, while the inheritance of this disease follows a simple pattern, the genes that control it reveal a much more complicated story than geneticists …

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